BONES OF UPPER LIMB : Side determination & Bony features

Overview of Upper Limb Bones

Introduction to Major Bones

• The video discusses the site determination and bony features of five major bones in the upper limb: clavicle, scapula, humerus, radius, and ulna.

Clavicle Features

• The clavicle is held horizontally; it has a flat lateral end and a quadrangular medial end that articulates with the sternum.

• Side determination involves recognizing the laterally flattened superior surface and concave anterior border versus convex posterior border.

• Key features include the conoid tubercle on the inferior side and trapezoid ridge for ligament attachment.

• When holding the clavicle, ensure that the smooth surface of the lateral third is superiorly positioned.

• The remaining shaft has a groove on its inferior side; this helps confirm it as a right-side clavicle.

Scapula Features

• The scapula (shoulder blade) is flat with three angles (lateral, inferior, superior), three borders (medial, lateral, superior), and two surfaces divided by spinous process.

• Glenoid cavity at the lateral angle forms part of the shoulder joint; hold this cavity laterally during examination.

• Superior border contains suprascapular notch; important for identifying orientation when determining sides.

• Three processes include coracoid process, acromion process, and spinous process; these are critical landmarks for identification.

• Dorsal side features supraspinous fossa above spinous process and infraspinous fossa below it.

Humerus Features

• The humerus has a round upper end (head) and broad lower end; key for side determination includes positioning medial epicondyle correctly.

• On upper end: head should be medially placed while lesser tubercle faces anteriorly and greater tubercle laterally.

• Important bony landmarks include anatomical neck at junction of head/shaft and surgical neck related to axillary nerve.

• Lower end features include medial/lateral epicondyles, capitulum/trochlea structures crucial for elbow joint articulation.

• Olecranon fossa accommodates olecranon process from ulna during flexion at elbow joint.

Radius Features

• Radius identified by its disc-shaped upper end versus broader lower end; styloid process present on lower part aids in identification.

• Radial tuberosity faces medially while sharp interosseous border aligns with ulna's corresponding feature.

• Lower end shows grooves/tubercles on posterior surface for extensor tendons while anterior remains smooth—key for distinguishing sides.

• Important bony features include rounded head at upper end followed by constricted neck leading to radial tuberosity.

Ulna Features

• Understanding ulna requires knowledge of its relationship with radius; sharp interosseous border faces laterally towards radius.

• Head of ulna accommodates radial head forming superior radioulnar joint which is essential in forearm movement.

Understanding the Anatomy of the Ulna

Key Features of the Ulna Bone

• The ulna features an olecranon process at its upper end, which fits into the olecranon fossa of the humerus located posteriorly.

• The head of the ulna is at its lower end, characterized by a broader proximal end and a narrower distal end; it also has a small projection known as the styloid process.

• For side determination, key features include: olecranon process (upper end), trochlear notch (faces forward), and radial notch (depression for joint with radius).

• The sharp lateral border and head are crucial for identifying that this is the right ulna; it accommodates with the radius at its lower end.

• The trochlear notch between coronoid and olecranon processes accommodates the trochlea of the humerus during movement.

Detailed Anatomical Structures

• Anterior to the coronoid process lies the ulnar tuberosity, while adjacent to it is another depression called radial notch.

• The supinator crest can be located by tracing along the interosseous border towards radial notch; it's important for muscle attachment.

• The upper part's interosseous border merges with supinator crest, leading towards posterior aspect of radial notch.

• On examining the shaft, three borders are identified: lateral (interosseous), anterior, and posterior (subcutaneous).

• At lower end features include head of ulna and styloid process; a groove exists between them allowing passage for extensor carpi ulnaris muscle.

Summary of Important Features

• Revisiting key structures: olecranon process, coronoid process, trochlear notch, ulnar tuberosity, radial notch, and supinator crest are essential in understanding ulna anatomy.

• Notably highlighted is that posterior border is subcutaneous in nature which may have clinical relevance.